Research On The Finite Element Model Modification And Damage Identification Of Bei Da Bridge In Dalian

Our country's strong support for infrastructure construction and people's constant pursuit of travel convenience have prompted the emergence of bridge structures across the country on a large scale.With the continuous accumulation of bridge using time,various diseases have appeared in the existing bridges,which will affect the usability and the safety of the structure,casing irreparable harm.Therefore,ensuring the normal use of the bridge structure has become the key work during the bridge operation.In order to monitor and master the state of structure in real time,the bridge health monitoring technology is gradually valued and used.The core and key point of real-time monitoring and evaluation of monitoring system is to select a suitable method for damage identification through the analysis of the accurate finite element model,and use this method for damage identification and positioning.BeiDa Bridge inDalian,as an important traffic highway in coastal area,joined the health monitoring system after reinforcement.In order to realize the function of health monitoring system in identifying early damage,the special research on the structure of it has become an urgent problem to be solved.This paper takes BeiDa Bridge inDalian as the research object to carry out the following work:(1)By consulting the relevant information and research literature at home and abroad,the finite element model modification technology and damage identification technology of bridge structures are summarized respectively,and their development process at home and abroad is briefly introduced.The basic principle of the key technology in finite element model modification and the basic principle of damage identification method based on the dynamic and static characteristics are systematically introduced.(2)The paper introduces the health monitoring system of Dalian BeiDa Bridge,selects the processing method of monitoring data,makes regression analysis of the temperature,deflection and strain data to obtain the temperature deflection and temperature strain coefficient as part of the target value of the model modification.(3)Using Midas/Civil to establish the initial finite element model of the bridge.Calculating the temperature response and static load response of the model,and compared with the measured data to determine the necessity of finite element model modification.(4)On the basis of sensitivity analysis of components,two steps of model updating are formulated to realize the modification of finite element model.(5)For the sudden damage of hanger or upper/lower chord of stiffening girder,the applicability of four damage indices of hanger force difference,deflection curvature difference,natural frequency difference and modal curvature difference is studied.(6)To analyze the sensitivity of hanger element and stiffening girder joint to damage indicators that can be used for damage location when sudden structural damage occurs.